Grinding wheel truing mechanism



oct. 26, 1943.

LVM. DAVIS GRINDING WHEEL TRUING MECHANIM Filed July l2, 1941 3 Sheets-Sheet l Oct. 26, 1943. M. DAvls GRINDING WHEEL TRUING MECHANISM Filed July 12, 1941 3 Sheets- Sheet 2v Oct. 26, 1943. l.. M. DAvls GRINDING WHEEL TRUING'f-MECHANI SM Filed July 12, l1941 3 sheets-sheet 3 Mmmafar/ME@ Patented Oct. 256, 1943 i I* vunirno-4 srrizs rieur orsi-ce GnrNnrNG WHEEL TRUINGMECHANISM Lee M. Davis, Springiield, Vt., assigner to Jones e Lamson Machine Company, Springiield,-Vt., a corporation of Vermont Application July 12, 1941, sena1N0.4o2,058

4 Claims.

In the Flanders Patent No. 2,184,011, for Grinding machine, granted December 1 9, 1939, is shown a mechanism for truing grinding wheels for cutting screw threads but when threads having considerable lead are to be ground, a greater truing tool vtraverse Ythan can be obtained by the mechanism shown in that'patent is necessary.

An object of this invention, therefore, is to provide a truing ymechanism by which such increasedv traverse is obtainable.

For a. more complete understanding of this invention, together with further objects and advantageous constructions, reference may be had to the accompanying drawings in which Figure 1 is a front end elevation of the mechanism with certain parts omitted.

Figures 2, 3, 6 and 10 are sectional views, Figures 3, 6 and 1G being fragmentary, on the correspondingly numbered section lines of Figure 1,

the section line for Figure 1.0 also appearing on Figure 3.

Figure 4 is a detail sectional view on line fi- Ci of Figure 3.

Figure 5 is a detail sectional view on line --i of Figure 2.

Figure 7 is a view similar to Figure 6, .but showing the side truing devices at the opposite limits of motion.

Figure 8 is a detail sectional View to a larger scale on line 8-8 of Figure 6.

Figure 9 is a detail sectional view on line 9,-9 of Figure 5.

Figure 11 is a sectional View on line ll-li of Figure 2.

Figure 12 is a fragmentary perspective lview showing a side truing device cam and its mountlng.

Figures 13 and 14 are end and side elevations. respectively, to a larger scale, of a cam member.

Figure 15 is a development of the cam of Figures 13 and 14.

Referring to the drawings, at l is indicated a tubular casing carrying the truing mechanism and which may be substituted for the truing mechanism and casing shown in the Flanders Patent No. 2,134,011. This casing l is provided with three transverse partitions 2, 3 and l between its ends. The partition 2, which is nearest to the grinding wheel, shown at 5 in Figures r6 and 7, is providedwith a transverse slot t f through which may be extended a pair of bars to the forward ends of which outside of the partition 2, are supported truing devices 3. An angle member 9 having a horizontal leg l projecting inwardly through the slot 'l and forming with to the shaft.

the base of this slot a guideway for the sliding reception of the bar 'l is provided with a vertical flange I I which may be adjustably secured to the outer face of the vpartition 2 as by means or screws l2. This angle member 9 retains the bars 1 down against the lower face of the slot E.

In order to prevent the entry of foreign matter into the casing through the slot 6, this slot is bridged over by a exible hood i4 secured to the partition 2 around the slot 6 by the clamping bars i5 and having openings through which the bars 'l project and make close contact with the sides of these bars. These bars 'l are L shaped in plan, being provided at their rear ends with lateral extensions 20 which extend away from each other. The rear ends of these bars thus widened by the extensions 23 have pivoted thereto the forward ends of a pair of links 2 l, the rear ends of which are in turn pivoted as at 22 to a carriage 23 mounted for rectilinear motion lengthwise of the casing l on a pair of guide `bars 24 and 25, opposite ends of which are mounted in perforated bosses in the partitions 2 and 3.

The links 2l, arranged in pairs, both links of each pair being pivoted to its corresponding bar '1, act together as a parallel motion permitting lateral motion of the bar ,'l, while restraining these bars 'i to remaining in parallel relation to each other. This is shown best in Figures 6 and '7, the bars 'l being shown in their inner positions in Figure 6 where they are relatively close together, and in their outer positions in Figure 7 where they are shown as projected well through the partition 2. bars 'i are shown as being maintained in parallel relationship by their double link connections to the carriage 23. i i f The carriage 23, at one side adjacent to the Aguide Vbar 25 is provided with a boss 2@ supporting a stub shaft on which is journaled a cam. roller 2i. This cam roller` 2i, as shown best in Figures 7 and 10, engages in a cam groove 23 of a barrel cam 2t secured to a rotary shaft 3S l i positioned between and with its axis slightly above the guide bars 24 and 25. This shaft Si] is arranged to be driven from a motor 3l carried by the casing i rearwardly of the partition l to the back tace oi which partition the motor 3i may be secured. The armature shaft 32 of this motor is connected through a coupling 33 to a shaft S4 carrying a Worm which meshes with a worm wheel 36 on a vertical shaft Si. This vertical shait El carries near its lower end a worm which meshes with a worm wheel 39 keyed This worm and Worm Wheel drive In both views, however, theseY connection acts as a reduction gearing, causing the shaft to be rotated at a very much slower speed than the armature shaft 32, such that the shaft 30 rotates once for each truing and return pass of the side truing tools 8, which complete truing pass constitutes a single complete truing cycle. The shaft 30 extends through a cover plate enclosing the rear end of the casing I and into a compartment 4I thereof which may contain electric switch mechanism having the controlling functions of the mechanism shown in the Flanders Patent No, 2,184,011 within the casing 2 I Il, the shaft 3U herein performing the functions of the shaft |29 shown in the Flanders patent. As in the case of the Flanders patent, this shaft 3U controls presentation of the truing devices to and retractions from the grinding wheel by the rocking back and forth of a threaded shaft 42 having a bearing against the end of a shaft 43 corresponding in function to the shaft 5I of the Flanders Patent No. 2,184,011. As this particular portion of the mechanism forms no part of the present invention, reference may be had to the Flanders Patent No. 2,184,011 for a more complete understanding thereof.

As the bars are moved lengthwise of the casing I by the motion of the carriage 23 they are also moved laterally from and toward each other in accordance with the side contour desired for the grinding wheel 5, which is shown herein as shaped to grind screw threads. tion of the side truing tools is produced by the action of cam mechanism. Such cam mechanism comprises a pair of oppositely disposed reversely faced edge cams 59, each of these cams being supported on an integral bracket portion 5| ex'- tending inwardly from the wall of the casing i. Each of the cams 5I! is pvoted, as on the vertical pin 52, to the top face of its bracket 5|, and its outer side face may engage against an adjusting stop screw 53 threaded through a bar 54 secured as by screws to the top face of the bracket 5I. A locking screw 536 extends through an arcuate slot 53| through the cam 59 and is threaded into the shelf 5I. Each of the cam plates 5i) has an edge cam face 55 across which may be traversed a follower 56 carried by a post 5T secured to the corresponding bar `I, and the followers 56 are held against their cam faces as by springs 58, each of these springs having one end secured to a bar l es at 59 and the opposite end secured to a fixed point 6i) of the casing I. Thus as the carriage 23 is reciprocated, the bars I are not only moved in and out, but transversely as well, in paths depending uponthe configurations of the earn faces 55.

As shown there is a third wheel truing device l0 carried by an arm 'II fixed to an axially movable and rockable shaft '12. This shaft I2 extends through an opening i3 through the partition I and a exible hood I4 through which the shaft l2 extends and which is secured about its margin to the forward face of the partition 2 around the opening 'i3 serves to seal this opening against the entry of foreign matter into the casing I back of the partition 2. This shaft 'I2 has a rearward extremity 'I5 of reduced cross section which extends into a bushing 'I6 in a bracket portion "VI of the partition 3 in alinernent with the shaft 34 which is journaled therein.

The shaft 'I2 is normally pushed toward its outer axial position as by a spring 89 surrounding the reduced diameter portion l5, one end of which spring bears on a shoulder 8| on the shaft i2 and the other end of which bears against the bushing 'I6 within which the rear end of the shaft This lateral mo- T2 is slidably and rockably mounted. This spring holds a collar 83 secured to the shaft '12, as

by a set screw 31|, into engagement with the upper end of a lever pinned to a rock shaft 8S back of the partition 2. The lower end of this lever 85 is formed as a cani follower 87 and rides in a groove 8S in the barrel cam 29. This groove 88 on its back face forms a cam 89 which acts, as the shaft 39 rotates, to oscillate the lever 85 and thus produce axial reciprocation of the shaft 'I2 and consequently of the end truing tool i9. This reciprocatory motion brings the end truing tool into and out of operative relation to the apex 98 of the grinding wheel 5. By oscillatory motion of the shaft 'I2 this truing tool is caused to traverse across this apex. This oscillatory motion is produced by an edge cam portion of the cam 29 adjacent to the peripheral groove 88, one side wall of which controls the rocking of they lever 85. As shown in Figure 5, this cam portion 95 acts upon a follower portion 9% of a lever 9i having a hub 99 journa-led on the guide bar 24. This lever 9'! has an arm 99 connected through a link |69 to an arm |UI extending from the block 83.

Connections from the link IUI] tothe arm |I)| and to the arm 99 may be made as shown in Figure 9, allowing a slight universal motion between these parts so as to permit the axial as well as the rocking motion of the shaft i2, while the hub 98 is held against axial motion. The connecting pivots I U2 for the ends of the link |09 may each therefore be provided with a spherical enlargement I3 inwardly of a head |04 and the link |90 may be provided with cylindrical sockets at its ends for engagement with the spherical portions |93 of the pins |92.

In order to take up lost motion between the cam 29 and the follower 2'1 which reciprocates the side bars "I, a friction device has been illustrated. This device comprises a bar H9 secured as by a screw to the rear portion of the carriage 23, this bar extending through a, perforation in the partition 3 and through a friction gland at H2 carried by the partition 4. As shown best in Figures 3 and 4, this gland comprises a bushing portion H3 seated in an opening through the partition l1 and having a flange H4 overlying the rear face of the partition. Back of this gland I|2 there is arranged a pair of blocks H5 and H6, each having an arcuate opening to engage on one side of the bar H9 and to be pressed toward each other to impart frictional drag to axial motion of the bar H9 by a pair of springs |I'I surrounding a pair of screws IIS. Each of these screws is threaded into the block H6 and has a head I I9 within a socket |29 in the block I i5 within which one of the springs I II is positioned, this spring reacting between the base of its socket and the head I I 9 of the screws. A pair of screws |25 passing through notches |26 in the blocks I5 and IIS and passing through the iiange IIL? and threaded into the partition 4 secure these blocks I I5 and I I5 in position.

Each of the side truing devices, 8 may be mounted Ion its bar I as shown best in Figure 8. Each device 8 is in the form of a cylindrical rod pointed at its outer end where it holds the cutting point. It is axially slide-ble through an opening |30 between upper and lower portions of a block |3I. This opening may have a V base against the side of which the device 8 is clamped by a set screw |32 and it is backed up by an adjustable plug |33 threaded through a back wall portion |34 of the upper portion of the block I3 I.

This block has a depending channel shaped portion 35, through the web of which a securing screw |36 threaded into the bar 1 extends.

In operation of this mechanism, rotation of the motor 3l from a rest position at the end of a truing cycle causes the casing I to advance toward the Wheel and then the bars 1 to be moved from the position of Figure 6 across the side faces of the wheel to the position of Figure 7 and return. During the advance of the side truing tool the edge truing tool is moved axially into operative relation to the apex of the grinding wheel and is rocked to traverse this apex. The apex truing tool is then retracted so as to get out of the way of the side truing tools. The casing as a whole is then retracted by the rotation of the shaft 3i! and its actionV on the threaded shaft 42, and the motor 3l is stopped. This cycle is the same as that of the truing` mechanism sho-wn in the Flanders Patent No. 2,184,011, to which reference has heretofore been made. By reason of the mounting of the side truing tools, however, a much greater amplitude of motion suitable for wheels of greater thickness than can be trued by the Flanders mechanism, can be trued by the mechanism of this invention.

From the foregoing description of an embodiment of this invention, it should be evident to those skilled in the art that various changes and modifications might be made without departing from the spirit or scope of this invention as defined by the appended claims.

I claim:

1. A wheel truing mechanism comprising a, support, a pair of side truing devices, means on said support for guiding said side truing devices for in and' out motion in intersecting paths, an end truing tool mounted on said support fol` rocking and axial motions, a rotary cam, connections from said cam for rocking said end truing tool,

and connections carried by said support from said side truing tools to said end truing tool for moving said end truing tool axially with the Ain and out motion of said side truing tool.

2. A wheel truing mechanism comprising a pair of side truing devices, means for` guiding said side truing devices for in and out motion in intersecting paths, an end truing tool mounted for rocking and axial motions, a rotary cam, connecand end truing tool for moving said end truing tool axially with the in4 and out motion of said side truing tool, said connections including universal pivotal parts facilitating both rocking and axial motion of said end truing tool. y

3. A Wheel truing mechanism comprising a, support, a rock shaft mounted for axial motion in said support, an arm carried by said shaft, a wheel truing device carried by said arm, a rotary shaft journaled in said support substantially parallel to said rock shaft, a cam carried by said rotaiy shaft and having edge and axial cam faces, a lever having a follower 4riding on said edge cam face, connections from said lever to said rock shaft for rocking said rock shaft to move said rock shaft acrossA said grinding wheel face by oscillation of said lever, said connections including a universal joint, a follower for said axial cam face, operative connections from said lastmentioned follower to said rock shaft causing axial motion of said rock shaft from said axial cam face to move said device into and out of wheel truing position, and means for rotating said rotary shaft.

4. A wheel truing mechanism comprising a casing, a rock shaft mounted for axial motion in said casing and projecting through a wall of said casing, an arm carried by said shaft outwardly of said wall, a wheel truing device carried by said arm, a rotary shaft journaled in said casing substantially parallel to said rock shaft, a cam carried by said rotary shaft and having a pair of cam faces, a lever having a follower riding on one of said cam faceaconnections from said lever to said rock shaft for rocking said' rock shaft to move said device across a grinding wheel face by oscillation of said lever, lsaid connections including a universal joint, a follower for the other of -said cam faces,- operative connections froml said last mentioned follower to said rock shaft causing axial motion of said rock shaft by motion of said last mentioned follower from said other cam face to move said device into and out of wheel truing position, and means for rotating said rotary shaft.

LEE DAVIS.

tions from said cam for rocking said end truing' tool, and connections from said side truing tools 

